Kodak
began experimenting with lens coatings
on a production basis in the later 1930s.
In his 1951 book, Lenses in Photography, Rudolf Kingslake, then Director
of Optical Design for Kodak, reports
that calcium fluoride, as an optical coating, was first offered for commercial
use in 1938, but its softness relegated it to inner surfaces. As other fluorides
were developed for lens coatings and the vacumn deposition techniques to
apply them were refined, the coated surfaces became as hard as the glass
they covered.

This illustration from the Kodak Data Book, Kodak Lenses, Shutters and
Portra Lenses, shows a schematic of the way lens coatings work to cancel
reflections. In the left frame, the lower half of the lens is coated, so
that reflections D and E are out of phase and cancel each other. The photograph
at the right is of a lens with one side coated and the other uncoated when
a bright light source is shown on the lens.

Kodak may have been discrete in
describing its early lens coating technologies because it was
experimenting with hard coating from roughly 1940 through 1945. Kodak
produced cameras, lenses, sighting devices and rangefinders for the U.
S. Army and Navy during WWII and perhaps tried different coatings for
different applications. It is possible that not all of the Kodak production
lines were updated with the capability of using coated lens elements at
the same time. While war-time advertisting was clearly anticipating the
postwar consumer market -- for example, in this Medalist ad
-- fixing the end date of the war would have been guesswork and revealing
information about things like the coatings on Aero Ektars was likely prohibited.

Based on Richard
Knoppow's pre-2000 inquiry with Kodak
, Kodak records of when they started applying coatings to their lenses
were no longer accessible. The collection of Kodak papers at the University
of Rochester might hold some information about lens coating practices
during this period. Michael
Briggs has examined a reasonably large sample of military Aero Ektars,
some as early as 1941, and found that all but one were coated, though
not marked with the characteristic .

While the table
below is anything but a comprehensive registry of Kodak lenses, I have
asked for and many visitors have responded with information about Kodak
lenses of this period. That has been helpful in trying to fill
in the gaps about early 1940s coatings. As of August 2010, there doesn't
seem to be a reason to update this table with data for hardcoated lenses
marked from 1946 onwards, nor for uncoated lenses manufactured before
1945. The following lenses are of still of interest in establishing Kodak
lens coating practices:

Lenses marked with before 1946

Coated unmarked lenses before 1946

Ektra Ektars of any age that appear to be hardcoated

Kodak lenses with the pre-CAMEROSITY numbering scheme that appear
to be coated.

Kodak professional lenses made after 1965, to define Kodak's last
contribution to this market

Please send information to the email
address at the bottom of this page. To avoid spam the address isn't clickable;
please enter the address in your email client. No information about the
owners will be published.

While later lenses will have an
obvious color tint in the glass, determining whether coating is present
is sometimes difficult with early lenses, often because these lenses have
fewer optical surfaces on which the coating is applied. Those involved
in Kodak's early coating process would have known how to differentiate
the appearance of uncoated, calcium fluroide-coated and magnesium fluroide-coated
glass; the rest of us have to rely on inference. EY Ektra Ektars almost
certainly would have had calcium fluroide-coated glass. They are pretty
indistinguishable from ER Ektra Ektars, which may have been hardcoated,
and more obviously coated than more modest mid-40s lenses that are Lumenized.
Uncoated lenses will have no colored refections off different optical
surfaces when a light sources is reflected at an oblique angle, whereas
the light source reflected off different surfaces of a coated lens will
appear in slightly different colors. Different light sources can affect
appearance.

Kodak Ektars from 1946 through 1965
were single-coated; and it is possible that some Ektars after 1965 were
multi-coated, though Kodak's offerings in the prosumer market by this
point were a trickle. Kodak AG lens production followed Kodak's U. S.
conventions; coated lenses were marked with ;
it is possible, but not very likely that late model Retinas may have been
multi-coated. Generally, the additional coating layers in multi-coated
lenses are designed to filter out reflections at wave lengths not filtered
by a single coating. About 1970, lens makers began the strategic application
of six or seven coatings that filter most frequencies of visible light.
The greater the number of air/glass surfaces, the greater the need for
effective coating. Multicoating of modern lenses with many elements, particularly
zoom lenses, is essential to maintain good contrast. For the kinds of
formulas used for most Ektars, multicoating would make only a marginal
contribution to flare reduction and then primarily in color.

Kodak research showed that lens
baffle design was as important as lens coating in reducing lens reflections
that decreased contrast, so cameras designed in the late 1930s and throughout
the 1940-50s had improved baffles and paint materials.

Kodak assigned
serial numbers to Anastigmat Special/Anastar and Ektar lens. Prior to
about 1940 it used a single numeric sequence, 54321†,
while serial numbers after that were alpha-numeric, two letters and three
or four numbers -- ES3682. The letters in the U. S. were mapped to the
word (sic) "CAMEROSITY", while in England, the mapping was to "CUMBERLAND".

Lenses are ordered by Kodak brand,
then by length. All shutters for Anastigmat Special/Anastar and Ektar
lenses are mounted in Kodak Supermatic or Flash Supermatic shutters unless
otherwise marked according to the legend in the footnotes.

LENS

SERIAL
NUM

NOTE

LENS

SERIAL
NUM

NOTE

ANASTIGMAT
SPECIALS/ANASTARS *

Ektar
90mm f/3.5
(Ektra) EFP

EY277 ('40)

Soft coated;

Anastig Spec
47mm f/4.5 (Bantam)
KOD

EY6752 ('40)

Not coated

Ektar 100mm f/3.5
(Medalist I)

EM128 ('43)

Soft coated

Anastig Spec
47mm f/4.5 (Bantam) KOD

ER7303 ('45)

Perhaps coated

Ektar 100mm
f/3.5
(Medalist II)

ES5885 ('47)

Coated

Anastig Spec
48mm f/4.5 (Flash Bantam) KOD

ES7697 ('47)

Coated

Ektar 100mm
f/3.5
(Medalist II)

ET205 ('49)

Coated

Anastig Spec
48mm f/4.5 (Flash Bantam) KOD

EI120164('48)

Coated

Anastar 50mm f/3.5
(Kodak 35 RF) KOD

EI6259 ('48)

Coated

Anastar 80mm f/3.5
(Kodak Reflex II)
KOD

---‡

Coated

Anastig Spec
101mm f/4.5 (Monitor)

EY2638 ('40)

Not coated

Ektar 100mm
f/3.5
(Medalist II)

ET582 ('49)

Coated

Anastig Spec
101mm f/4.5 (Monitor)

EO3652 ('46)§

Probably coated

WF Ektar 100mm
f/6.3

EI346 ('48)

Coated

Anastig Spec
101mm f/4.5
(Senior)

EO9578 ('46)

Coated

Ektar 101mm
f/4.5

E03946 ('46)

Uncoated

Anastig Spec
101mm f/4.5 (Monitor)

EO11398('46)

Coated

Ektar 101mm
f/4.5

ES3682 ('47)

Coated

Anastig Spec
101mm f/4.5 (Monitor)

EO14297 ('46)

Coated

Ektar 101mm
f/4.5

ES14029 ('47)

Coated

Anastig Spec
127mm f/4.5 (Senior)

EC1511 ('41)

Not coated

Ektar 101mm
f/4.5

EI205 ('48)

Coated

Anastig Spec
127mm f/4.5 (Monitor)

EC1685 ('41)

Probably coated

Ektar 101mm
f/4.5

EI314 ('48)

Coated

Ektar 107mm
f/3.7

No. 562

May be soft
coated

Ektar 127mm
f/4.7

EE3160 ('44)

Not coated

Ektar 127mm
f/4.7

EE4647 ('44)

Not coated

Ektar 127mm f/4.7

EE1384 ('44)

Coated

Ektar 127mm
f/4.7

ER6584 ('45)

Not coated

Ektar 127mm
f/4.7

ER7138 ('45)

Not coated

Anastar 101mm
f/4.5 (Tourist II) KSR

RA2237 ('52)

Coated

Ektar 127mm
f/4.7

ES2525 ('47)

Coated

.

.

.

Ektar 127mm
f/4.7

ES7918 ('47)

Coated

Ektar 127mm
f/4.7

EI7637 ('48)

Coated

Ektar 127mm
f/4.7 SC

RC5900 ('51)

Coated

Ektar 127mm
f/4.7 SC

RM1333('53)

Coated

ANASTIGMAT
EKTARS, EKTARS, COMMERCIAL EKTARS, WIDE FIELD EKTARS

Ektar 127mm
f/4.7 SC

RI284 ('58)

Coated

Anastig Ektar
45mm f/2.0 (Bantam Spec) CR

15700

Not coated

Ektar 127mm f/4.7

RI2875 ('58)

Coated

.

.

.

Ektar 135mm
f/3.8
(Ektra) EFP

ER255 ('45)

Soft coated;
maybe hard coated;

.

.

.

Ektar 152mm
f/4.5

EO961 ('46)

Coated

Ektar 44mm
f/3.5
(Signet) KOD

RC54598 ('51)

Coated

Ektar 152mm
f/4.5

ES963 ('47)

Coated

Ektar 44mm
f/3.5 (Signet) KOD

RE17883 ('54)

Coated

.

.

.

Ektar 44mm
f/3.5 (Signet) KOD

RR1959 ('55)

Coated

Ektar 7 1/2
f/4.5 ACME

EI 687 ('48)

Coated

Ektar
7 1/2 f/4.5 ACME

0
- EI 1630¶('48)

Coated

Ektar
50mm f/1.9 (Ektra) EFP

EY1254 ('40)

Soft coated

Ektar 7 1/2
f/4.5 ACME

OR120 (''65)

Coated

WF Ektar 190
f/6.3 ACME

EI778 ('48)

Coated

Ektar 203mm f /7.7

EE1384 ('44)

Coated

Ektar 50mm
f/3.5
(Retina) CR

EO25826 ('46)

Coated

Ektar 203mm
f /7.7

EE1384 ('47)

Coated

Ektar 78mm
f/3.5
(Prototype)

ES0001 ('47)

Coated

Ektar 203mm
f /7.7

EI1524 ('48)

Coated

Ektar 78mm
f/3.5
(Chevron) KSR

RM2747 ('53)

Coated

Ektar 203mm
f /7.7

RA763 ('53)

Coated

Ektar 203mm
f /7.7 SC

RT385 ('59)

Coated

WF Ektar 80mm
f/6.3

EI810('48)

Coated

WF Ektar 80mm
f/6.3

EI908 ('48)

Coated

Commercial
Ektar 10" f/6.3 ACME

OS163 ('67)

Coated

WF Ektar 80mm
f/6.3

EI1048('48)

Coated

*Anastigmat Specials were essentially
the same as Anastars, but earlier ones were uncoated. Glass compounds in the
Anastars may have been updated.
§Although this
lens is not marked with ,
it has the same characteristic color as the other '46 FAS. Prior to 1940, Kodak used a numeric
serial number for lenses, but I have seen so few of these that I know nothing
about the
structure of the numbering system
or the pattern
to their assignment. ‡On the Kodak Reflex II,
the lens identification is not stamped or engraved on the retaining
ring for the front element, but on
on the outer metal rim of the lens mount which is a
cast aluminum piece with cogs that serve as the focusing interface between
the viewing and the taking lens.
The lens ID information does not include
a serial number, unique I think, for KASs and Anastars.¶
I know of two examples of this lens that have a '0' or 'O' prefix, but I have
no information about its significance.
EFPEktra
focal plane shutter
GSCGRAPHICSynchro Compur shutterKOD Kodamatic ShutterSC Synchro Compur shutterKSRKodak Synchro Rapid shutterCR Compur Rapid shutterACME
Acme Shutter

TENTATIVE
CONCLUSIONS

Visible differences between
uncoated, softcoated and hardcoated Kodak lenses were relatively subtle
between 1940 and 1965 when compared to the appearance of modern multi-coated
lenses, but some differences in coloration of reflections should be
noticeable.

While hardcoating of Kodak
lenses may have begun as early as 1940, this wasn't generally discussed
in public documents until 1946, when the term Lumenizing emerged.

Regardless of the presence
of hardcoating in a growing fraction of advanced amateur and professional
lenses from 1941 through 1945, few had the Lumenizing mark
before 1945.

The only collector reporting
any pattern in hardcoating prior to 1946 is Michael Briggs, a collector
of Aero Ektars, who has noticed that most were hardcoated. Some elements
have a yellowish-brown color, which he suggests may have become that
color over time due to radioactive properties in some of the glasses
used. Some of this coloration may have been intended to increase haze
reduction in these aerial lenses.

All Ektra Ektars, the Ektars
in Medalists, the Ektars in Bantam Specials made after about 1940,
and large format Eastman Ektars made after about 1940, at a minimum,
had soft calcium fluoride coating applied to inner surfaces. When
harder fluroides were introduced to particular models, these would
have replaced calcium fluoride.

The single example of an Ektra
Ektar made on or after 1946 was not hard coated. Ektra Owners: More
data would obviously be useful. The serial numbers on Ektra Ektars
are not on the lens ring, but are stamped in the metal on the shank
of the lens that is placed in the camera's lens mount. So far it isn't
clear whether Kodak embossed the
on hardcoated Ektra Ektars.

How were the serial numbers
assigned? Sequentially by year or sequentially by lens model? Given
the relatively high serial numbers of some lenses, and that Kodak
probably wanted a unique number on each lens, it appears to me that
a single annual sequence was used. To have assigned numbers by model,
would have produced many duplicate numbers and made public use of
these as identifying numbers very confusing. If lens rings were produced
in a single shop, they likely would have been produced in batches.
Perhaps, if the shop were going to make 50 rings for 80mm WF Ektars,
they took the last number used and started their run from that point.
If production was more dispersed or done in parallel operations, perhaps
they assigned ranges of numbers based on projected production. Note
the close proximity of numbers in many cases for lenses of the same
type and year. An experienced Ektra collector has developed some hypotheses
about Kodak serial numbering .